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On the behaviour characterization of metallic cellular materials under impact loading

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Acta Mechanica Sinica 2010年第6期26卷 837-846页

作者： Dai-Ning Fang yu-long li Han Zhao College of Engineering Peking University 100871 BeijingChina School of Aeronautics Northwestern Polytechnical University 710072 Xi'anChina Laboratoire de Mecanique et Technologie ENS-Cachan/CNRS-UMR8535/Universite Pierre and Marie Curie61avenue du president Wilson 94235 Cachan CedexFrance

This paper reviews the common mechanical features of the metallic cellular material under impact loading as well as the characterization methods of such behaviours. The main focus is on the innovations of various testing methods at impact loading *** aspects were discussed in details.（1） The use of soft nylon Hopkinson/Kolsky bar for an enhanced measuring accuracy in order to assess if there is a strength enhancement or not for this class of cellular materials under moderate impact loading;（2） The use of digital image correlations to determine the strain fields during the tests to confirm the existence of a pseudo-shock wave propagation inside the cellular material under high speed impact：（3） The use of new combined shear compression device to determine the loading envelop of cellular materials under impact multiaxial loadings.

关键词： Foam Honeycomb Lattice Hopkinson bar Rate sensitivity

Formation of adiabatic shearing band for high-strength Ti-5553 alloy:A dramatic thermoplastic microstructural evolution

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Defence Technology（防务技术） 2022年第11期18卷 2045-2051页

作者： Dong-yang Qin Ying-gang Miao yu-long li School of Aeronautics Northwestern Polytechnical UniversityXi'an710072China School of Civil Aviation Northwestern Polytechnical UniversityXi'an710072China

By using split Hopkinson pressure bar, optical microscopy and electronic microscopy, we investigate the influence of initial microstructures on the adiabatic shear behavior of high-strength Ti-5Al-5V-5Mo-3Cr(Ti-5553) alloy with lamellar microstructure and bimodal microstructure. Lamellar alloy tends to form adiabatic shearing band(ASB) at low compression strain, while bimodal alloy is considerably ASBresistant. Comparing with the initial microstructure of Ti-5553 alloy, we find that the microstructure of the ASB changes dramatically. Adiabatic shear of lamellar Ti-5553 alloy not only results in the formation of recrystallized β nano-grains within the ASB, but also leads to the chemical redistribution of the alloying elements such as Al, V, Cr and Mo. As a result, the alloying elements distribute evenly in the *** contrast, the dramatic adiabatic shear of bimodal alloy might give rise to the complete lamination of the globular primary a grain and the equiaxial prior β grain, which is accompanied by the dynamic recrystallization of a lamellae and β lamellae. As a result, ASB of bimodal alloy is composed of a/β nanomultilayers. Chemical redistribution does not occur in ASB of bimodal alloy. Bimodal Ti-5553 alloy should be a promising candidate for high performance armors with high mass efficiency due to the processes high dynamic flow stress and excellent ASB-resistance.

关键词： Titanium alloys Armor High loading rate Adiabatic shearing band Dynamic phase transformation

Cellular and Molecular Mechanisms Underlying Arterial Baroreceptor Remodeling in Cardiovascular Diseases and Diabetes

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Neuroscience Bulletin 2019年第1期35卷 98-112页

作者： Huiyin Tu Dongze Zhang yu-long li Department of Emergency Medicine University of Nebraska Medical CenterOmahaNE 68198USA

Clinical trials and animal experimental studies have demonstrated an association of arterial baroreflex impairment with the prognosis and mortality of cardiovascular diseases and diabetes. As a primary part of the arterial baroreflex arc, the pressure sensitivity of arterial baroreceptors is blunted and involved in arterial baroreflex dysfunction in cardiovascular diseases and *** in the arterial vascular walls, mechanosensitive ion channels, and voltage-gated ion channels contribute to the attenuation of arterial baroreceptor sensitivity. Some endogenous substances(such as angiotensin II and superoxide anion) can modulate these morphological and functional alterations through intracellular signaling pathways in impaired arterial baroreceptors. Arterial baroreceptors can be considered as a potential therapeutic target to improve the prognosis of patients with cardiovascular diseases and diabetes.

关键词： Cardiovascular disease Diabetes Baroreflex Baroreceptor Vascular wall Mechanosensitive ion channels Voltage-gated ion channels Angiotensin Ⅱ Superoxide Nuclear factor-kappa B

Application of split Hopkinson tension bar technique to the study of dynamic fracture properties of materials

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Acta Mechanica Sinica 2012年第2期28卷 424-431页

作者： Ze-Jian Xu yu-long li Feng-Lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology100081 BeijingChina School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

A novel approach is proposed in determining dy- namic fracture toughness （DFT） of high strength steel, using the split Hopkinson tension bar （SHTB） apparatus, com- bined with a hybrid experimental-numerical method. The center-cracked tension specimen is connected between the bars with a specially designed fixture device. The fracture initiation time is measured by the strain gage method, and dynamic stress intensity factors （DSIF） are obtained with the aid of 3D finite element analysis （FEA）. In this approach, the dimensions of the specimen are not restricted by the connec- tion strength or the stress-state equilibrium conditions, and hence plane strain state can be attained conveniently at the crack tip. Through comparison between the obtained results and those in open publication, it is concluded that the ex- perimental data are valid, and the method proposed here is reliable. The validity of the obtained DFT is checked with the ASTM criteria, and fracture surfaces are examined at the end of paper.

关键词： Split Hopkinson tension bar Dynamic fracture toughness Hybrid experimental-numerical method High loading rate Failure mode

A QICAR Model for Metal Ion Toxicity Established via PLS Method

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Chemical Research in Chinese Universities 2013年第3期29卷 568-573页

作者： li yu JIANG long li Xiao-li HU Yan WEN Jing-ya Resources and Environmental Research Academy North China Electric Power University Beijing 102206 P. R. China

The partial least squares（PLS） method was employed to establish a quantitative ion characteristics-activity relationship（QICAR） model for metal ion toxicity（EC50 of 15 metal ions）. The ion characteristics included AN（the atomic number）, AIP（the change in ionization potential, eV）, Xm（the electronegativity, eV）, AW（the atomic weight）, Xm2r（the covalent index）, △E0（the absolute difference between electrochemical potential of the ion and that of its first stable reduced state, eV）, ｜lgKoH｜（the absolute value of the lg of the first hydrolysis constant）, AR（the atomic radius, nm）, AR/AW（the ratio between atomic radius and atomic weight） and ap（the softness index） selected based on relative correlation analysis. The simulated and tested（with the other four metals） efficiency coefficients of the model are 0.88 and 0.96, respectively. The information revealed from the QICAR model indicates that the value of the metal ion toxicity was positively correlated with variables AN, AlP, Xm, AW and Xm2r; negatively correlated with variables AE0, ｜IgKoH｜, AR/AW, AR and ap, and ion characteristics △E0, Xm, σp and Xm2r were found to contribute more to the toxicity of metal ions via the accurate analysis method provided by PLS. The model could be used to predict the toxicity of the target metals and preliminary to assess combined pollution and environmental risk for heavy metals in the environments.

关键词： Quantitative ion characteristics-activity relationship Partial least square Metal ion characteristic Metal toxicity Accurate analysis

Comparative Study on Solid-State and Metastable liquid-State Aging for SAC305/Cu Joints

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 629-637页

作者： Shuang li Xiao-Wu Hu Wei-Guo Zhang yu-long li Xiong-Xin Jiang Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang University College of Mechanical and Electronic Engineering Northwest A&F University

In order to study the in?uence of the physical state of solder on the interfacial reaction of dip-soldered Sn-3.0 Ag-0.5 Cu/Cu system, two kinds of experiments were designed, including:(1) solid-state aging between the solder and Cu substrate;(2)liquid-state aging between the metastable supercooled liquid-state solder and Cu substrate. The aging times were 30, 60,120 and 180 min, respectively, and the aging temperature was 8 ℃ lower than the melting point of the Sn-3.0 Ag-0.5 Cu(SAC305) alloy(217 ℃). The experimental data revealed that the physical state of the solder obviously affected the formation of the intermetallic compound(IMC), and resulted in the difference in the diffusion of atoms on the interface between the SAC305 solder and Cu substrate. The IMC interface after aging for 30 min presents unique characteristics compared with that of the sample after dip soldering. The IMC interface of solid-state aged SAC305/Cu couple is relatively planar, while the IMC interface under metastable supercooled liquid-state aging conditions presents scallop-like shape.

关键词： Lead-free solder Supercooling Metastable liquid state Aging Intermetallic compound

Cross-linked Electrospun Gel Polymer Electrolytes for lithium-Ion Batteries

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Chinese Journal of Polymer Science 2024年第8期42卷 1021-1028页

作者： Xue Gong Qin Xiao Qing-Yin li Wen-Cui liang Feng Chen long-yu li Shi-Jie Ren College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

lithium-ion batteries(liBs)benefit from an effective electrolyte system design in both terms of their safety and energy storage ***,a series of precursor membranes with high porosity were produced using electrospinning technology by mixing PVDF and triblock copolymer(PS-PEO-PS),resulting in a porous structure with good interconnections,which facilitates the absorbency of a large amount of electrolyte and further increases the ionic conductivity of gel polymer electrolytes(GPEs).It has been demonstrated that post-cross-linking of the precursor membranes increa ses the rigidity of the nanofibers,which allows the polymer film to be dimensionally sta ble up to 260℃while maintaining superior electrochemical *** obtained cross-linked GPEs(CGPEs)showed high ionic conductivity up to 4.53×10^(-3)S·cm^(-1).With the CGPE-25,the assembled li/liFeP04 half cells exhibited good rate capability and maintained a capacity of 99.4%and a coulombic efficiency of99.3%at 0.1 *** results suggest that the combination of electrospinning technique and post-cross-linking is an effective method to construct polymer electrolytes with high thermal stability and steadily decent electrochemical performance,particularly useful for lithium-ion battery applications that require high-temperature usage.

关键词： Electrospinning Cross-linked Gel polymer electrolytes lithium-ion batteries

Synthesis, Crystal Structure and Biological Activities of 2-(4-Fluorophenyl)-2-oxo-1-(1H-1,2,4-triazol-1-yl) ethyl morpholine-4-carbodithioate

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Chemical Research in Chinese Universities 2005年第6期21卷 673-676页

作者： XU liang-zhong ZHU Chong-yi yu Chen-long li Kai SI Guo-dong College of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China

The title compound, 2-（ 4-fluorophenyl ） -2-oxo-1-（ 1H-1, 2,4-triazol-1-yl ） ethyl morpholine-4-carbodithioate, was synthesized and its structure was confirmed by means of IR, MS, 1 H NMR and elemental analysis. The single crystal structure of the title compound was determined by X-ray diffraction. The preliminary biological test showed that the synthesized compound possesses some biological activities.

关键词： 1H-1,2,4-Triazole Morpholine Crystal structure Biological activity

Substructure Prediction from Infrared Spectra by Using Support Vector Machines

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Chinese Chemical Letters 2005年第10期16卷 1354-1356页

作者： Jun Hong liU Min Chun LU Fu Sheng NIE Xiao yu FENG Meng long li College of Chemistry Sichuan University Chengdu 610064

The potential of support vector machines （SVMs） for the substructure elucidation of infrared spectra have been investigated. The trained SVMs can identify the 16 substructures with high accuracy.

关键词： Infrared spectra substructures support vector machines.